当x/y=2/3时,4x+3y/3x-5y=_______

当x/y=2/3时,4x+3y/3x-5y=_______
当x/y=2/3时,4x+3y/3x-5y=_______

当x/y=2/3时,4x+3y/3x-5y=_______
设x=2t,y=3t,t≠0,则
(4x+3y)/(3x-5y)
=(4*2t+3*3t)/(3*2t-5*3t)
=17t/(-9t)
=-17/9

x/y=2/3
3x/2=y
4x+3y/3x-5y=[4x+(3*3x/2)]/[3x-5*(3x/2)]
=17/9
填空的话
直接取 x=2 y=3 再算 得 17/9

-17/9
(4x+3y)/(3x-5y)=(4x/y+3)/(3x/y-5)=(8/3+3)/(2-5)=-17/9